DIY party streamers - These zig zag party streamers are soooo easy! I chose jewel toned construction paper and cut 4 at a time. I had my family help so it didn't take long. We used them for New Year's decorations. Hanging them in doorways as curtains and from fans as streamer chandeliers. They would probably look cute from our front porch as well. You could probably use cool printed scrapbook paper as well. Easy and cheap party decorations!

Repinned especially for Jenn Mitroff! Not sure if you're looking for rainbow party ideas or whatev, but this kinda goes with some of the party ideas you're pinning. Looks SUPER simple, too! You could get the whole wild gang in on this one! ;)

Used in Dance Party - DJ lance hat - musical chairs with pics of characters on them the person sitting on the character gets to wear the hat and play muno's guitar // Mary Pat's Birthday Party | Gabba Friends

A lot of the rainbow party ideas in this link fit well with an art theme. Tons and tons of birthday, holiday, and shower themes (Another pinner said: so many that you could spend days on this site...LITERALLY.)

M+M 3rd birthday cake, via Enchanted Mommy | Made this for my youngest nephew's third birthday party -- super easy and super fun! I used Bakerella's chocolate cake recipe (http://www.bakerella.com/just-a-cake/) as the base, made two 6-cup bundt cakes and went to town with the M The M soften after a few hours on the icing so the cake was pretty easy to eat too.

A number cake! I think I will wait until Scott's 3rd birthday because it's a bunt cake and the number 2 would be too hard to do.

Fun kids birthday cake idea

Awesome 3rd Birthday Cake idea. Two bundt cakes and candy.

27 Amazing birthday cake ideas: Via @babycenter #birthdaycakes Don't know how I'd ever make a number 3 but I like this idea... gotta be easier than a rainbow cake right?